1. Field of Invention
The present invention relates to a backlight module and a liquid crystal display (LCD) incorporating the same, and more particularly, to a backlight module having a positioning structure and to an LCD including the backlight module.
2. Description of Related Art
A backlight module is one the fundamental parts of an LCD. Since the LCD itself does not emit light, the backlight module is needed to provide the required light source. In the backlight module, a light guide plate is used to direct the light emitted from a backlight source as a planar light source, thereby assuring the uniformity of lightness. A backlight commonly used in the backlight module can be such as a cold cathode fluorescent lamp (CCFL) and a light emitting diode (LED), etc. Although the CCFL is the main trend currently, the demands for using the LED have been increasing daily. In comparison with the CCFL, the LED has the advantages of environmental protection, small size, long operation life, low driving voltage, low power consumption and excellent shock resistance, etc.
In general, when light emitting diodes are applied in an LED backlight module, the light emitting diodes are first disposed on a flexible print circuit board (FPC), and then the flexible print circuit board is folded and inserted into a mold frame for disposing the light emitting diodes adjacent to one side of a light guide plate. Meanwhile, the distance and angle between the light emitting diodes and the light guide plate has quite a great influence on the output luminance and lightness uniformity of the light guide plate, thus affecting the quality of the backlight module, further determining if the LCD using the backlight module is with good quality. Hence, how to accurately position the light emitting diodes to closely contact the light guide plate has become quite an important issue.
Conventional skills intend to make the assembly of the light emitting diodes (or an FPC) and the module to meet the requirement of high accuracy by using specific assembling methods, tape adhesion or the design of positioning the FPC, etc. However, the conventional skill using specific assembling methods cannot actually demand all of the workers to have consistent assembling movements. Especially in mass production, the assembling movements among the works will be different, and it is difficult to establish the standards for determining if the assembling movements are consistent. Further, the conventional skill using tape adhesion causes the increase of the production cost, and not all of the related product mechanisms have sufficient space for receiving the tape for adhesion. If the adhesive area of the tap is not enough, the light emitting diodes will be displaced easily. Further, the conventional skill using the design of positioning the FPC has the following disadvantages. While the product is increasingly miniatured, the FPC or mold frame may not have enough space for forming holes, pillars and ribs to fabricate a positioning device; and the positioning device must have certain tolerances, and thus the assembly of the light emitting diodes (or an FPC) and the module fails to meet the requirement of high accuracy.